sql server 2008中的apply运算符使用方法

create table StudentList(
id int Identity(1,1) not null,
Name nvarchar(20) not null,
Sex bit not null,
Birthday date not null,
Class nvarchar(2) not null,
Grade nvarchar(2) not null,
regdate date not null,
Primary key (id));

create table ScoreInfo(
id int Identity(1,1) not null primary key,
StudentID int not null,
ClassID int not null,
Score int not null,
TestDate date not null,
regdate date not null);

insert into StudentList(Name, Sex, Birthday, Class, Grade, regdate) values('张三', 1, '1988-05-28', 1, 8, '2010-05-05');

insert into StudentList(Name, Sex, Birthday, Class, Grade, regdate) values('李四', 1, '1985-09-13', 4, 4, '2010-05-05');

insert into StudentList(Name, Sex, Birthday, Class, Grade, regdate) values('王丽', 0, '1987-11-05', 1, 7, '2010-05-05');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(1, 1, 98, '2010-04-15', '2010-05-01');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(1, 2, 92, '2010-04-15', '2010-05-01');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(1, 3, 86, '2010-04-15', '2010-05-01');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(2, 1, 95, '2010-04-15', '2010-05-01');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(2, 2, 94, '2010-04-15', '2010-05-01');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(2, 3, 91, '2010-04-15', '2010-05-01');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(3, 1, 90, '2010-04-15', '2010-05-01');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(3, 2, 88, '2010-04-15', '2010-05-01');

insert into ScoreInfo(StudentID, ClassID, Score, TestDate, regdate) values(3, 3, 90, '2010-04-15', '2010-05-01');

insert into StudentList(Name, Sex, Birthday, Class, Grade, regdate)
values('李铭', 1, '1989-05-04', 2, 7, '2010-05-05');

select * from StudentList a
cross apply
(select ClassID, Score from ScoreInfo where StudentID=a.id) b;